engine stalling and hesitating after warmed up.
 

Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.

Engine stalls and runs poorly AFTER heating up.

I can often get it to idle or run at just above idle just fine (that's
how I got it home) but too much throttle and it keeps choking, then
catching, then choking again. There's no place on the throttle range
that runs well, which makes me *not* suspect the TPS - should I? If I
floor it, it runs at low RPMs but sounds horrible (and no power).

I changed the fuel filter - no change. Since it runs fine until hot, I
don't suspect the fuel pump - should I?

This begin occurring immediately after it sat for a few months while I
was out of town, in a humid tropical environment. It's hell on cars
here and I'm suspecting one of the sensors is out of whack but I don't
know which one to look at first.

Oh, and the only ODB code is 1-2-5-5. Battery disconnected.

Any help is terribly appreciated!

Elijah

Re: engine stalling and hesitating after warmed up.
 

elijahs wrote:
> Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
>
> Engine stalls and runs poorly AFTER heating up.
>
> I can often get it to idle or run at just above idle just fine (that's
> how I got it home) but too much throttle and it keeps choking, then
> catching, then choking again. There's no place on the throttle range
> that runs well, which makes me *not* suspect the TPS - should I? If I
> floor it, it runs at low RPMs but sounds horrible (and no power).
>
> I changed the fuel filter - no change. Since it runs fine until hot,
> I don't suspect the fuel pump - should I?
>
> This begin occurring immediately after it sat for a few months while I
> was out of town, in a humid tropical environment. It's hell on cars
> here and I'm suspecting one of the sensors is out of whack but I don't
> know which one to look at first.
>
> Oh, and the only ODB code is 1-2-5-5. Battery disconnected.

How old are the plugs/wires/rotor/cap?
How old is the coil?

A failing coil will cause all sorts of bucking and problems
when it gets warm.

Go ahead and disconnect the TPS. The vehicle will run
without it. See what that does. If the engine smooths
out then it is either the TPS or the connection.

Check the engine ground strap and see if it has rotted.
You can test for a faulty engine ground by putting a jumper
between the engine and the frame or battery ground.

--
DougW

Re: engine stalling and hesitating after warmed up.
 

elijahs wrote:
> Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
>
> Engine stalls and runs poorly AFTER heating up.
>
> I can often get it to idle or run at just above idle just fine (that's
> how I got it home) but too much throttle and it keeps choking, then
> catching, then choking again. There's no place on the throttle range
> that runs well, which makes me *not* suspect the TPS - should I? If I
> floor it, it runs at low RPMs but sounds horrible (and no power).
>
> I changed the fuel filter - no change. Since it runs fine until hot,
> I don't suspect the fuel pump - should I?
>
> This begin occurring immediately after it sat for a few months while I
> was out of town, in a humid tropical environment. It's hell on cars
> here and I'm suspecting one of the sensors is out of whack but I don't
> know which one to look at first.
>
> Oh, and the only ODB code is 1-2-5-5. Battery disconnected.

How old are the plugs/wires/rotor/cap?
How old is the coil?

A failing coil will cause all sorts of bucking and problems
when it gets warm.

Go ahead and disconnect the TPS. The vehicle will run
without it. See what that does. If the engine smooths
out then it is either the TPS or the connection.

Check the engine ground strap and see if it has rotted.
You can test for a faulty engine ground by putting a jumper
between the engine and the frame or battery ground.

--
DougW

Re: engine stalling and hesitating after warmed up.
 

elijahs wrote:
> Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
>
> Engine stalls and runs poorly AFTER heating up.
>
> I can often get it to idle or run at just above idle just fine (that's
> how I got it home) but too much throttle and it keeps choking, then
> catching, then choking again. There's no place on the throttle range
> that runs well, which makes me *not* suspect the TPS - should I? If I
> floor it, it runs at low RPMs but sounds horrible (and no power).
>
> I changed the fuel filter - no change. Since it runs fine until hot,
> I don't suspect the fuel pump - should I?
>
> This begin occurring immediately after it sat for a few months while I
> was out of town, in a humid tropical environment. It's hell on cars
> here and I'm suspecting one of the sensors is out of whack but I don't
> know which one to look at first.
>
> Oh, and the only ODB code is 1-2-5-5. Battery disconnected.

How old are the plugs/wires/rotor/cap?
How old is the coil?

A failing coil will cause all sorts of bucking and problems
when it gets warm.

Go ahead and disconnect the TPS. The vehicle will run
without it. See what that does. If the engine smooths
out then it is either the TPS or the connection.

Check the engine ground strap and see if it has rotted.
You can test for a faulty engine ground by putting a jumper
between the engine and the frame or battery ground.

--
DougW

Re: engine stalling and hesitating after warmed up.
 

On Fri, 24 Nov 2006 17:39:39 -0800, elijahs wrote:

>
> Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
>
> Engine stalls and runs poorly AFTER heating up.
>
> I can often get it to idle or run at just above idle just fine (that's
> how I got it home) but too much throttle and it keeps choking, then
> catching, then choking again. There's no place on the throttle range
> that runs well, which makes me *not* suspect the TPS - should I? If I
> floor it, it runs at low RPMs but sounds horrible (and no power).
>
> I changed the fuel filter - no change. Since it runs fine until hot, I
> don't suspect the fuel pump - should I?
>
> This begin occurring immediately after it sat for a few months while I
> was out of town, in a humid tropical environment. It's hell on cars
> here and I'm suspecting one of the sensors is out of whack but I don't
> know which one to look at first.
>
> Oh, and the only ODB code is 1-2-5-5. Battery disconnected.
>
> Any help is terribly appreciated!

Last time I got that (last 5 miles home were at idle to maybe 1000 RPM
max) I had the CPS lead shorted out against the exhaust where I forgot to
tie it back). It would start and idle, but no way would the engine
accelerate or run at higher RPMs. Talk about a "limp home" mode!

Re: engine stalling and hesitating after warmed up.
 

On Fri, 24 Nov 2006 17:39:39 -0800, elijahs wrote:

>
> Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
>
> Engine stalls and runs poorly AFTER heating up.
>
> I can often get it to idle or run at just above idle just fine (that's
> how I got it home) but too much throttle and it keeps choking, then
> catching, then choking again. There's no place on the throttle range
> that runs well, which makes me *not* suspect the TPS - should I? If I
> floor it, it runs at low RPMs but sounds horrible (and no power).
>
> I changed the fuel filter - no change. Since it runs fine until hot, I
> don't suspect the fuel pump - should I?
>
> This begin occurring immediately after it sat for a few months while I
> was out of town, in a humid tropical environment. It's hell on cars
> here and I'm suspecting one of the sensors is out of whack but I don't
> know which one to look at first.
>
> Oh, and the only ODB code is 1-2-5-5. Battery disconnected.
>
> Any help is terribly appreciated!

Last time I got that (last 5 miles home were at idle to maybe 1000 RPM
max) I had the CPS lead shorted out against the exhaust where I forgot to
tie it back). It would start and idle, but no way would the engine
accelerate or run at higher RPMs. Talk about a "limp home" mode!

Re: engine stalling and hesitating after warmed up.
 

On Fri, 24 Nov 2006 17:39:39 -0800, elijahs wrote:

>
> Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
>
> Engine stalls and runs poorly AFTER heating up.
>
> I can often get it to idle or run at just above idle just fine (that's
> how I got it home) but too much throttle and it keeps choking, then
> catching, then choking again. There's no place on the throttle range
> that runs well, which makes me *not* suspect the TPS - should I? If I
> floor it, it runs at low RPMs but sounds horrible (and no power).
>
> I changed the fuel filter - no change. Since it runs fine until hot, I
> don't suspect the fuel pump - should I?
>
> This begin occurring immediately after it sat for a few months while I
> was out of town, in a humid tropical environment. It's hell on cars
> here and I'm suspecting one of the sensors is out of whack but I don't
> know which one to look at first.
>
> Oh, and the only ODB code is 1-2-5-5. Battery disconnected.
>
> Any help is terribly appreciated!

Last time I got that (last 5 miles home were at idle to maybe 1000 RPM
max) I had the CPS lead shorted out against the exhaust where I forgot to
tie it back). It would start and idle, but no way would the engine
accelerate or run at higher RPMs. Talk about a "limp home" mode!

Re: engine stalling and hesitating after warmed up.
 

ok - coil, rotor, cap, wires all just replaced. Plugs are maybe a
year old.

The engine runs no differently at idle with the TPS disconnected.

Yeah, I'm starting to suspect the CPS. I'm gonna try jumping the frame
to the engine first, though.

It's getting worse - now it's pretty reluctant to idle. I can start it
cold, it'll run for 10-12 minutes, and then suddenly die and be a real
bear to get anything out of it.

no codes still.


Will Honea wrote:
> On Fri, 24 Nov 2006 17:39:39 -0800, elijahs wrote:
>
> >
> > Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
> >
> > Engine stalls and runs poorly AFTER heating up.
> >
> > I can often get it to idle or run at just above idle just fine (that's
> > how I got it home) but too much throttle and it keeps choking, then
> > catching, then choking again. There's no place on the throttle range
> > that runs well, which makes me *not* suspect the TPS - should I? If I
> > floor it, it runs at low RPMs but sounds horrible (and no power).
> >
> > I changed the fuel filter - no change. Since it runs fine until hot, I
> > don't suspect the fuel pump - should I?
> >
> > This begin occurring immediately after it sat for a few months while I
> > was out of town, in a humid tropical environment. It's hell on cars
> > here and I'm suspecting one of the sensors is out of whack but I don't
> > know which one to look at first.
> >
> > Oh, and the only ODB code is 1-2-5-5. Battery disconnected.
> >
> > Any help is terribly appreciated!
>
> Last time I got that (last 5 miles home were at idle to maybe 1000 RPM
> max) I had the CPS lead shorted out against the exhaust where I forgot to
> tie it back). It would start and idle, but no way would the engine
> accelerate or run at higher RPMs. Talk about a "limp home" mode!

Re: engine stalling and hesitating after warmed up.
 

ok - coil, rotor, cap, wires all just replaced. Plugs are maybe a
year old.

The engine runs no differently at idle with the TPS disconnected.

Yeah, I'm starting to suspect the CPS. I'm gonna try jumping the frame
to the engine first, though.

It's getting worse - now it's pretty reluctant to idle. I can start it
cold, it'll run for 10-12 minutes, and then suddenly die and be a real
bear to get anything out of it.

no codes still.


Will Honea wrote:
> On Fri, 24 Nov 2006 17:39:39 -0800, elijahs wrote:
>
> >
> > Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
> >
> > Engine stalls and runs poorly AFTER heating up.
> >
> > I can often get it to idle or run at just above idle just fine (that's
> > how I got it home) but too much throttle and it keeps choking, then
> > catching, then choking again. There's no place on the throttle range
> > that runs well, which makes me *not* suspect the TPS - should I? If I
> > floor it, it runs at low RPMs but sounds horrible (and no power).
> >
> > I changed the fuel filter - no change. Since it runs fine until hot, I
> > don't suspect the fuel pump - should I?
> >
> > This begin occurring immediately after it sat for a few months while I
> > was out of town, in a humid tropical environment. It's hell on cars
> > here and I'm suspecting one of the sensors is out of whack but I don't
> > know which one to look at first.
> >
> > Oh, and the only ODB code is 1-2-5-5. Battery disconnected.
> >
> > Any help is terribly appreciated!
>
> Last time I got that (last 5 miles home were at idle to maybe 1000 RPM
> max) I had the CPS lead shorted out against the exhaust where I forgot to
> tie it back). It would start and idle, but no way would the engine
> accelerate or run at higher RPMs. Talk about a "limp home" mode!

Re: engine stalling and hesitating after warmed up.
 

ok - coil, rotor, cap, wires all just replaced. Plugs are maybe a
year old.

The engine runs no differently at idle with the TPS disconnected.

Yeah, I'm starting to suspect the CPS. I'm gonna try jumping the frame
to the engine first, though.

It's getting worse - now it's pretty reluctant to idle. I can start it
cold, it'll run for 10-12 minutes, and then suddenly die and be a real
bear to get anything out of it.

no codes still.


Will Honea wrote:
> On Fri, 24 Nov 2006 17:39:39 -0800, elijahs wrote:
>
> >
> > Ok - 1992 Cherokee Sport 4.0L, auto, 110k miles.
> >
> > Engine stalls and runs poorly AFTER heating up.
> >
> > I can often get it to idle or run at just above idle just fine (that's
> > how I got it home) but too much throttle and it keeps choking, then
> > catching, then choking again. There's no place on the throttle range
> > that runs well, which makes me *not* suspect the TPS - should I? If I
> > floor it, it runs at low RPMs but sounds horrible (and no power).
> >
> > I changed the fuel filter - no change. Since it runs fine until hot, I
> > don't suspect the fuel pump - should I?
> >
> > This begin occurring immediately after it sat for a few months while I
> > was out of town, in a humid tropical environment. It's hell on cars
> > here and I'm suspecting one of the sensors is out of whack but I don't
> > know which one to look at first.
> >
> > Oh, and the only ODB code is 1-2-5-5. Battery disconnected.
> >
> > Any help is terribly appreciated!
>
> Last time I got that (last 5 miles home were at idle to maybe 1000 RPM
> max) I had the CPS lead shorted out against the exhaust where I forgot to
> tie it back). It would start and idle, but no way would the engine
> accelerate or run at higher RPMs. Talk about a "limp home" mode!